KIEV (AFP) - Ukraine was set to unveil a new prime minister and cabinet on Tuesday as top Western envoys rushed to Kiev to try to find a lasting solution to the crisis rocking the economically-teetering country.

Ukraine has appealed to the West for US$35 billion (S$44 billion) in aid to avoid default as the nation tilts away from Russia, following the weekend ousting of pro-Moscow president Viktor Yanukovych after days of carnage in Kiev left almost 100 dead.

Mr Yanukovych has since been slapped with an arrest warrant for "mass murder", capping more than three months of relentless protests against his rule sparked by his November decision to spurn an historic pact with the European Union in favour of closer ties with Russia.

EU foreign policy chief Catherine Ashton arrived in Kiev on Monday as the Ukrainian capital slowly returned to normal, with shops and restaurants in the centre re-opening, and she was due to brief the press at 0930 GMT Tuesday.

She met with interim leader Oleksandr Turchynov, who has warned that Kiev will have no alternative but to default on US$13 billion in foreign obligations due this year should the West fail to come to the aid of the economically-struggling country.

Adding to the diplomatic effort, Washington is sending Deputy Secretary of State William Burns to Kiev on Tuesday, and British Foreign Secretary William Hague is due to visit Ukraine soon.

While Western powers have cautiously thrown their weight behind the overthrow of democratically-elected Yanukovych, Russia has reacted with outrage to the "mutiny" in a country with centuries-old roots to Moscow.

The United States has stopped short of endorsing Ukraine's interim leader and called for a technocratic government to promote early elections.

Mr Turchynov has vowed to draw up a "government of the people" and warned Russia that he expects the Kremlin to respect Ukraine's pivot to the West.

On Tuesday, the electoral commission said the campaign for presidential polls set for May 25 had officially kicked off, though who exactly will stand for the top post remains to be seen.

The interim premier and Cabinet set to be announced on Tuesday will have the tough tasks of keeping stability in Ukraine ahead of the polls.

The political and financial crises rocking Ukraine have seen the nation of 46 million face the dire threat of splintering between its pro-Western, Ukrainian-speaking agrarian west and the Russian-speaking industrialised south and east.

Russia's foreign ministry on Monday strongly criticised the new Western-leaning leadership in Ukraine, saying it was restricting "the humanitarian rights of Russians".

"They have set a course to suppress those who do not agree in various regions of Ukraine using dictatorial and sometimes even terrorist methods," the ministry said in a statement.

The country also faces a devastating default, and finance chiefs from Europe, the United States and the International Monetary Fund have been discussing how to help out Ukraine.

Ukraine's interim finance minister Yuriy Kolobov said the "planned volume of macroeconomic assistance for Ukraine may reach around US$35 billion" by the end of next year.

He called for an international donors conference, an appeal also made by Greece which currently holds the EU presidency to avoid "disorder and default". Russia's vocal displeasure at the changes convulsing its neighbour has translated into fears that a much-needed US$15-billion bailout from Moscow announced in December may be abandoned after only one payment of US$3 billion came through.

The crisis in Ukraine also helped fuel a rise in oil prices on Monday, with analysts saying an angry Russia could halt natural gas supplies as it has done in the past.

"The threat and uncertainty surrounding Ukraine has Europe slowing exports of oil and products as they fear they may need them if they have to use them to offset the loss of Russian gas," said Mr Phil Flynn of Price Futures Group.

The whereabouts of Yanukovych, meanwhile, remained unknown.

Acting interior minister Arsen Avakov, who issued the arrest warrant on Monday, said he had tried to flee the country on Saturday out of the eastern city of Donetsk - his political power base and bastion of pro-Russian support - before escaping to Crimea, a base of Russia's Black Sea fleet, with a team of guards and a cache of weapons the next day.

He said the deposed head of state and his powerful administration chief Andriy Klyuev had since "travelled by three cars into an unknown direction, having first switched off their modes of communication".

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